Cigarette smoking and glycaemia: the EPIC-Norfolk Study. European Prospective Investigation into Cancer.
International Journal of Epidemiology 2001 ; 30: 547-54.
DOI : 10.1093/ije/30.3.547
PubMed ID : 11416081
Previous prospective studies have suggested that cigarette smoking may be associated with an increased risk of type 2 diabetes, but the possibility of confounding, particularly by dietary factors has not been fully examined.
Cross-sectional analysis of the association between cigarette smoking and HbA(1C), a marker of long-term glucose homeostasis in 2704 men and 3385 women, aged 45--74 years who were recruited to a population-based study of diet and chronic disease.
Twelve per cent of men and 11% of women reported being current smokers. Mean HbA(1C) was lowest in never smokers, intermediate in former smokers and highest in current smokers. There was a dose-response relationship between HbA(1C) levels and number of cigarettes smoked per day and a positive association with total smoking exposure as measured by pack-years. The unadjusted increase in HbA(1C) for 20 pack-years of smoking was 0.12% (95% CI : 0.09--0.16) in men and 0.12% (95% CI : 0.08--0.17) in women. After adjustment for possible confounders including dietary variables, the values were 0.08% (95% CI : 0.04--0.12) and 0.07% (95% CI : 0.02--0.12) for men and women, respectively. Mean HbA(1C) was inversely related to time since quitting smoking in men.
These results add support to the hypothesis that smoking has long-term effects on glucose homeostasis, an association that cannot be explained by confounding by dietary factors as measured in this study.
Study : EPIC-Norfolk: The European Prospective Investigation into Cancer Norfolk Cohort